In manufacturing semiconductor devices, a plasma processing is performed on a substrate by exciting a processing gas with energy supplied from a plasma source in a processing container. That is, a processing of etching a substrate is performed. As a plasma processing apparatus for use in such a plasma processing, a plasma processing apparatus including a radial line slot antenna has been recently developed (see Patent Document 1).
In the plasma processing apparatus described in Patent Document 1, a slot antenna having a plurality of slots is provided above a dielectric window of a processing container. A central introduction port of a central introducing unit is formed in the center of the dielectric window to supply a processing gas. Further, a peripheral introducing unit for supplying a processing gas is formed between the dielectric window and a placing table on which a substrate is placed. The peripheral introducing unit is provided below the central introduction port and includes an annular pipe that extends circumferentially in a space above the placing table. The annular pipe includes a plurality of peripheral introduction ports that are opened towards a central axis of the annular pipe. The central introducing unit and the peripheral introducing unit are connected to a processing gas source through a flow splitter.
The energy of microwaves radiated from the plurality of slots of the slot antenna is introduced into the processing container through the dielectric window. The processing gas introduced into the processing container by the central gas introducing unit and the peripheral gas introducing unit is converted into plasma by the energy of microwaves. Thus, the substrate is etched by the processing gas which has been converted into plasma.